1. Field
Exemplary embodiments relate generally to display device. More particularly, embodiments of the invention relate to degradation compensator of organic light emitting diode display device.
2. Description of the Related Art
Since an organic light emitting diode (“OLED”) display device displays an image using an OLED that generates light, the OLED display device doesn't need a light source (e.g., a backlight unit) unlike a liquid crystal display device (“LCD”). Thus, the OLED display device may be relatively thin and light. In addition, the OLED display device may have advantages of low power consumption, improved luminance, improved response speed, etc., compared to the LCD. Hence, the OLED display device is widely used as a display device included in an electronic device.
In a case of a pixel circuit which displays the same pattern consistently with high luminance in a display panel included in the OLED display device, e.g., a portion displaying a company logo such as “NBC” or “CBS”, a mobility of the driving transistor is degraded because of strong and consistent current applied thereto. After degradation of the pixel circuit, image sticking occurs on the pixel circuit so that viewers may see the logo on another image that does not intend to display the logo.
The image sticking may be removed when a degradation level or stress applied to the display panel of the OLED display device is calculated accurately. For accurate calculation of the stress, stress accumulation values, which is in proportion to sum of luminance which each part of the display panel have emitted light with, may be stored as a stress matrix form. Because the stress matrix requires a very large sized storage, the stress matrix is linearly transformed, compressed, and accumulated.